Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Data [Abstract]

Schedule of Quarterly Financial Information

	Quarter Ended
	December 31,		September 30,		June 30,		March 31,
	2018		2018		2018		2018
	(in thousands, except per share amounts)
Revenues	$	483,849	$	467,221	$	456,322	$	458,303
Operating income		150,321		138,006		125,870		129,969
Depreciation, accretion, and amortization		(169,454)		(167,703)		(169,558)		(165,398)
Loss from extinguishment of debt, net		—		—		(13,798)		(645)
Net income (loss)		57,152		16,144		(57,392)		31,547
Net income (loss) per common share - basic	$	0.50	$	0.14	$	(0.50)	$	0.27
Net income (loss) per common share - diluted		0.50		0.14		(0.50)		0.27
	Quarter Ended
	December 31,		September 30,		June 30,		March 31,
	2017		2017		2017		2017
	(in thousands, except per share amounts)
Revenues	$	443,073	$	433,945	$	427,294	$	423,362
Operating income		119,081		117,011		114,590		107,819
Depreciation, accretion, and amortization		(162,643)		(161,907)		(159,520)		(159,030)
Loss from extinguishment of debt, net		—		—		(1,961)		—
Net income		7,660		49,161		9,233		37,600
Net income per common share - basic (1)	$	0.07	$	0.41	$	0.08	$	0.31
Net income per common share - diluted		0.06		0.41		0.08		0.31

(1) The sums of quarterly earnings per share data may not equal annual data due to rounding.